[Intel-gfx] [PATCH] drm/i915: Disable TRAINING_PATTERN_SET before stopping the TPS transmission

[Imre Deak]

On Mon, Jan 18, 2021 at 06:21:07PM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> DP spec says:
> "The Source device shall start sending the idle pattern after
>  it has cleared the Training_Pattern byte in the DPCD."
> 
> Currently we do these in operations in the opposite order.
> Swap them around to match the spec.
> 
> Cc: Imre Deak <imre.deak at intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Makes sense:
Reviewed-by: Imre Deak <imre.deak at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dp_link_training.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index d8c6d7054d11..2d3396bfc207 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -697,9 +697,9 @@ static bool intel_dp_disable_dpcd_training_pattern(struct intel_dp *intel_dp,
>   * @intel_dp: DP struct
>   * @crtc_state: state for CRTC attached to the encoder
>   *
> - * Stop the link training of the @intel_dp port, disabling the test pattern
> - * symbol generation on the port and disabling the training pattern in
> - * the sink's DPCD.
> + * Stop the link training of the @intel_dp port, disabling the training
> + * pattern in the sink's DPCD, and disabling the test pattern symbol
> + * generation on the port.
>   *
>   * What symbols are output on the port after this point is
>   * platform specific: On DDI/VLV/CHV platforms it will be the idle pattern
> @@ -713,10 +713,9 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp,
>  {
>  	intel_dp->link_trained = true;
>  
> -	intel_dp_program_link_training_pattern(intel_dp,
> -					       crtc_state,
> -					       DP_TRAINING_PATTERN_DISABLE);
>  	intel_dp_disable_dpcd_training_pattern(intel_dp, DP_PHY_DPRX);
> +	intel_dp_program_link_training_pattern(intel_dp, crtc_state,
> +					       DP_TRAINING_PATTERN_DISABLE);
>  }
>  
>  static bool
> -- 
> 2.26.2
>